The performance sound systems used by rock music groups, and numerous other organizations, have two modes: operational and transportational. The operational mode is of course of great importance, but the transportational mode has much more importance than is generally recognized by sound system manufacturers. The ideal system would be one that is very satisfactory in both modes.
Getting from one performance (gig) location to the next, while carrying the sound system, is often a huge pain for rock music groups. Only a very few travel by private jet and helicopter; most groups go by van, commercial aircraft, bus, train, etc. This often involves going up and down stairs and escalators, through balky doors, etc. It often means standing and waiting--not infrequently in the rain. It always involves trying to get the system there in good condition, with no lost or damaged components.
Once it arrives at the gig site, the performance sound system must be set up in such a way as to maximize the quality of sound generation and projection, and the convenience of operating the controls. And, the set-up must be done in accordance with the particular physical (environmental) conditions that happen to be present. Is the gig on a theater stage? In a gym? In an open-air location? These and other very different types of surroundings mean that the set-ups must be different in order to be optimal for the particular performance.
For example, in a gym it may be optimum to set the speakers on the floor but directed somewhat upwardly. On a stage it may be optimum to mount the speakers on stands, at heights that vary from place to place.
The same is true for the mixing console-amplifier, especially a hands-on one as distinguished from what are called "tote box" mixers (these having fixed settings throughout a performance). Hands-on mixers are conventionally in flat boxes that are mounted horizontally. There is a need for a very different type of hands-on mixer, one that can be mounted at any elevation and can be vertical not horizontal.
The sound system must be powerful--performance caliber as distinguished from something that might be used only in a living room or den of a home. But it is emphasized that "performance" denotes not only rock music gigs but also meetings or gatherings at any place whatever where public address systems are used. There are at least hundreds of different types of such places.